Power-driven lawn mower



April 16, A. E. JERRAM 1,709,791

' POWER DRIVEN LAWN MOWER Filed March 23, 1927 5 Sheets-Sheet l 1Z/Z/ 57I \119 1220522167" fi Jermm WALQ' pig t,

u fi'ormfyx April 16, 1929. A. E. JERRAM POWER DRIVEN LAWN MOWER FiledMarch 23, 1927 5 Sheets-Sheet 2 a .w 0 1 %m y 0 z 9%8 0 9w 5 5 0 V .n 00J Ml m J II I n 5 :9 7M1. 8 l H wdfi 7 9w Wm flu o w w a M 1 v April16,1929. A. E. JERRAM 1,709,791

POWER DRIVEN LAWN MOWER Filed March 25, 1927. 5 Shets-Sheet 3 1 Inner/$7QZE'. Jzrram p 6, 1.929. A. E. JERRAM" 1,709,791

POWER DRIVENLAWN MOWER Filed March 25, 1927 5 SheetsShet 4 April 16,1929. A. E. JERRAM POWER DRIVEN LAWN MOWER Filed March 23, 1927 5Sheets-Sheet Patented Apr. 16, 1929.-

FFICE.

ARTHUR ERNEST JERRAM, or m ENGLAN POWER-DRIVEN LAWN MOWER.

Application filedMarch 23, 1927, Serial No.

This invention relates to power-driven lawn mowers of the typecomprising a rotary cutter. Such machines comprise a large number ofmechanisms of different kinds, includ- 5 ing the power-unit, arotarycutter, a driving roller, and driving gear between the powerunit, thecutter and the roller. As such machines are frequently worked under verysevere and varying conditions exposed to the weather and dirt and areused by persons,

such as gardeners, who are not skilled mechanics it is veryimportantthat each of these mechanisms shall be well designedand-skillfully arranged in conjunction with the rest in order tocontribute to the satisfactory working of the machine as a whole with aminimum of attention. Y I In a machine of the type described it hasheretofore been proposed to provide a changespeed gear, but this wasarranged to. alter the speed of travel of the machine as a wholeaccording to the power required-to drive it under varying eonditions andnot to vary the speed of rotation of the rotary cutter anddrivinggroller in relation one to the other,

/ This invention has for its main object the provision of an improvedconstruction of a power-driven lawn mower of the rotary cutter typebetter fitted than constructions proposed heretofore to' satisfy the.varying working conditions met with and to enable the mov-' ingelements to co-operate one with another in the most direct and eflicientmanner.

Another object is the provisionof driving gear of improved constructionbetween the power-unit and the rotary cutter and back roller. A furtherobject is to protect the rotary cutter and also the power-unit in animproved manner from injur owing to the rotary cutter and ledgerbla ebeing forced too hard into contact by adjustment or owing to anobstacle, such as twigs, a stone or the ground or too thick grassgettingtrapped 1 betweenvthe two. A still further object is to enablethe rate at which the back roller is driven to b varied'at will inrelationto the rate at wh'ch the rotary cutteris driven, in ordertoenable a power-unit "that'is just powerful enough fpr ordinary use toremove a specially heavy crop of grass, or to climb adients, or toobtain a specially smooth nish of a close-cut lawn. According toanimportant feature of the invention, there is provided a power-drivenlawn-mower comprising the combination of 177,791, and in Great BritainApril 1, 1926.

a frame, a rotary cutter and a driving'rollcr journalled therein, apower-unit carried by said frame,- transmission means operativelyconnecting the power-unit with said cutter and said roller, whichtransmission means comprises an engine-driven driving shaft and achange-speed which change-speed gear is ofthestep-bystep type having aplurality of pairs of gear Wheels of different gear ratios, and acontrolling device for thechange-speed gear for selecting at will'any ofthe said gear ratios and thereby varying the speed of said cutter" androller in relati ,n one to the other and the speed of one of them inrelation .to that of the power-unit, for the purposes of enabling a.motorthat is just powerful enough for norgear driven by the'latter,

mal use when driving the roller at one speed to be capable of being usedfor heavier work I a such as cutting a heavy crop of grass or climbingup a gradient when driven at a lower speed, and enabling the mower toim- 4 part a very smooth finish to a close-cut lawn With machines of therotary cutter type in which a series of cutter blades shear inter'mittently during the progress of the machine over the lawn, a certainamount of ribbing takes place, particularly in certain conditions fofthe grass, that is to say witha smooth shaven lawn a series of whatappear like fine sand ripples can be observed. In the improvedconstruction the intermittently acting cutters can be speeded up so thatthis ripple is made much finer, whilst the -'machine is still'availablefor cutting at what is, in practice, the best timed intermittent actionfor general purposes.

According to another feature of the invention prises a manuallycontrollable clutch ar ranged to disengage the driving. connectionbetween the motor and roller. This clutch is i preferably providedbetween the said'changespeed gear and the back roller.

According to a further feature of the in vention, the frameof the mowercomprises a rigid. side member formed as or providing a casing in'theform of a gear-box wherein said change-speed gear and also a driving.connection between a power-un'it-driven shaft and preferably chargedwith oil so that themechanism therein runs constantly in oil'. Accordito yet another featureof the] invention, t e power-unit is mountedspaced said power-transmission means comthe cutterare housed.This-casing is away from the gear-boxon cross members of the framesecured to said sldemember, and a mam dI'lVlIlg shaft extending 1nto thegear-box is connected to the power-unit crank-shaft by a self-adjustablecoupling g. a self-a igning flexible coupling) for preventing thetransmission mechanism from being subjected to stresses due to fiexureof the frame members carrying the power-unit.- According to stillanother feature of the I invention, a lawn mower having the features setforth above is provided with a slip clutch between the power unit andthe rotary cutter, and is characterized in that the said clutchcomprises clutch discs whereof the opposed engaging faces are ribbed orotherwise so- I .formed as to give a warning sound when the.

clutch is slipping. Further, when such-a clutch is combined with'devicesto hold it disengaged the 'mow-er can be temporarily used as aower-driven roller onl Other. eatures of the invent on will be describedhereinafter andpointed out in the claims; I l -Oneembodiment of theinventionis diagrammatically illustrated by way of 'example in theaccompanying drawings. In. said draw1ngs 1 Figure 1 is a perspectiveview of a com- .plete power-driven lawn-mower according to theinvention;

Figures 2 and 2 are a plan thereof, with some parts removed and othersbroken away and partly in section, to show the slip, clutch. andchange-speed gear aforesaid and other features, andmechanism for drivingthe roller;

Figure 6 is a vertical section taken onthe line 6-6 in Figure 5, and.

Figure 7 is a horizontal Sectional view taken on the line 77 in Figure6; I

Figure'S is a side elevation ofthe front end of the mower frame carryingthe front roller and itsadjusting device, and

Figure 9 is a vertical sectional elevation taken on the line 9 -9 inFigure 8; and

Figure 10 is a side elevation, partly in section, showing part of oneside member'of the frame and the mechanism for adjusting the, carrier ofthe ledger blade.

Some of the figures-are drawn on a scale different from' that of theothers, but like reference numerals designate like parts throIu h o utthe-several views.

ReQI- ipg tothe drawings, the powerdriven lawn-mower (Figure has a framedesignated generally by the numeral 10, comprising two side members 11,12, connected together by three main cross members 13, 14,

between the side members. below the middle stretcher rod 15.

' A rotary cylindriccutter 20 has its shaft 21 journalled in ,ballbearings at 22 and 23 in the side members between the front stretcherrod 13 and the distance rods 16, 17,

so as .to be'readily detachable in any convenient' manner, butpreferably as described in the prior Patent No. 1,486,758. A driving orback roller designated. generally by the the distance rods 16, 17 andtherear stretcher rod 14, and a front roller made in sections,designated generally by the numeral 27, is

journalled in the side members between the cutter 20 and the frontstretcher rod 13.

A power-unit designated generally by the numeral 30, in the form of anairand watercooled internal-combustion engine, for'drivin the cutter 20and back roller 24 is detachably supported at three points on the backand middle stretcher rods 14, 15 by readily detachable fasteningdevices, in'such amanreference numeral 24 is journalled by ball bearings25, 26 in the side members between nerthat it can be readily removedin'case of v need. For this purpose the crank-case is formed or providedwithtwo arms 31, 32 respectively extending fore and aft of the machine.The rear arm 32 terminates in a designated generally by the numeral 35which can be closed on the stretcher rod by a single bolt 36 that ispivoted on the fixed jaw 33 and extends through a hole on the movablej-aw 34. The front arm 31 of the crank-case is 'detachably securedto-the middle stretcher stretcher rod 15 along the entire length of theclip. The motor is thus provided with a.

three-point support on the frame, so that even if the stretcher rods 14,15 carrying/1t flex laterally the motor will not be subjected to f anymaterial bending stresses andthe al1gnsleeve 33, 34 that issplitlongitudinally and Y ment of its hearings will not be affected.

Y39*. If desired the clip affording two points of support may engage therod 15 and the clip 37 may engage the rod 14, but the arrangementillustrated-is that preferred.

The preferred construction of power-unit, as shown in Figures 1, 2 and3, is awatercooled internal-combustion engilie 30 wherein a relativelysmall water-supply tank shaped like a circular bowl is formed orprovided directly on the water acket41 forming part of the head of theengine, and is 0 en above to the atmosphere and is prefera 1y situatedin view of the operator'of the mower when the machine is in use. Theemployment of a radiator is thus obviated; the water simply boils awayand can be readily replenished when needed, because alawnmower when inuse is always not far from a water supply, and the water tank can bereadily seen by the operator, it being prefer-' ably always under' hiseye when in use. In

- this way a satisfactory engine is obtained without any materialaddition to the weight of the mower, andfurthermore a readily detachablemotor can be used without having to break complicated water joints orthe like such as are likely to be beyond the capacity of the ordinarygardener to attend to.

The'engine 30 cooled as aforesaid is disposed in a slanting position andthe body of the water jacket 41 is, for the purpose describedhereinafter, in the form of n annular chamber. at the cylinder head andsurrounds only a short length of the cylinder 42 at the end adjacent thehead, and the supply tank 40 opens into the upper portion of the saidannular chamber. The purpose of using an annular chamber is to leave thecentre of the cylinder head, which may be a detachable aluminium head,free for the ignition plug wh ch is thus readily accessible and yet willbe efficiently cooled by the jacket which is kept of small dimensionsand nevertheless ensures good circulation. The tank'or water pot 40 ispreferably of hemispherical shape and may be integral with the body 41of the jacket.

An impeller 43, for example a radial flow impeller, is preferablyarranged to be driven by the engine crank-shaft 44 for producing a blastof air and means are providedfor directing the blast against thatportion of the body of the cylinder 42 not surrounded by the waterjacket 41. As illustrated, this impeller 43 is in the form of afly-wheel mounted on the crank shaft, and the blastdirecting means is inthe form of a casing 45 surrounding the fiy-wheel, which casing has anaxial inlet at 46 and an outlet at 47 so arrangedet-hat a current of;air is induced by the impeller :toflow past the" crank case for coolingth ter. When the engine cylinder is par u cooled and partly air cooledDriving gear designated generallyrby the 4 numeral 50operativelyoonnects the motor 30 with the rotary cutter 20 and thedriving roller 24, andpreferably comprises a main driving shaft 51 thatlies. parallel with the said stretcher rods 13,14, 15 and is engageddirectly by a coupling 52, 53 with the motor crank shaft '44 which isalso parallel with the stretcher rods. This coupling 52, 53 may be aslip coupling of any convenient construction that enables thetwo shafts44, 51 to be disengaged and engaged by a simple movement of the motor ina direction parallel with the stretcher rods or in a direction atright-angles thereto. As illustrated the slip coupling takes the form ofa self-adjusting coupling of the Oldham type, whereof one element 53 isformed on the impeller .43 and separate power transmission meansdesignated generally by the numeral 56 (Figures 2 and 5.) connecting themain shaft 51 with the back roller 24. The side frame member 12 isformed as a casing for housing these transmission means 55, 56, and theupper part of the rear end, of this casing 12 preferably constitutes achange-speed gear box' 57 in which said main driving shaft 51 isjournalled in ball 'bearings 58. At the side of these bearings remotefrom the motor this shaft 51 carries a cutter-driving sprocket wheel 59which is'free to rotate on the shaft and is geared by a chain 60 with adriven sprocket wheel 61 fast in said casing 12 on the shaft'21 of therotary cutter 20. For clutching the driving sprocket wheel 59 to itsshaft 511a slip clutch of any convenient form may be provided. In thepreferred construction illustrated '(Figures 2 and 4) one clutch disc62. slidable on the shaft 51 towards and away frpm a co-operating clutchdisc '63 formed on the sprocket wheel 59 is controlled spring 64 tendingto hold the discs inclutching engagement, and disen-,

gaging means designated generally by the numeral 65 may be provided forat times llOldf ing the spring-controlled clutch disc 64 out ofengagement with the co-operating'disc 63'. Thesedisengaging means 65comprise a bolt 66 that is movable endwise in an axial bore 1 the bolt66. The key 68 fits in the slot 169 but has playin the slot 69 in.thedirection of length of the shaft 51. A disengaging nut 70 is' providedon the end of the bolt 66 which extends out :of the shaft 51. i This nutco-operates with the adjacent end of,

the shaft, and, when screwed up, will move the bolt 66 endwise in thebore 67 and thereby move the spring-controlled clutch disc into itsdisengaged position and hold it therein 'against the action of. its.spring 64 as shown in Figure 4. A light spring 71 at the ot-herend ofthe bolt 66 tends to move it in the direction for disengaging theclutch.

These two clutch discs 62, are preferably corrugated on theirco-operating faces or otherwise so formed that when the clutch slips anoise, such as a warning buzz, is set up to notify the operator that thecutter 2O 0 is not being driven by the motor.

The transmission mechanism 56 (Figure 5) for driving the back roller 24comprises a hollow lay shaft 75 in the gear-box 57 that carries two gearwheels 76, 77 with which sliding gear wheels 7 8, 79 on the main drivingshaft can be engaged by means of a change-speed lever 80 (Figure 1)mounted on the gear-box 57. This lever 80 controls a double sliding fork81 which embraces the sliding gear wheels 78, 79 and is mounted i toslide on a rod 82 carried in the gear-box struction of this clutchcomprises a series of drivin discs 85 slidably keyed on the end ofthelay shaft remote from the motor, a driven disc 186'that has a seriesofdisc-skeyed freely to it and carries the sprocket'wheel 84, a bolt 87that extends through the lay shaft 75 and has at one end a head 88bearing against the driving disc 85, a flanged collar 89 ,and lock nut90 at the other end, and a compression spring 91 in a recess "92 intheadjacentend of the lay shaft 75 abutting at one end against ashouldertherein and at the other end? against the collar 89, which spring 91.tcnds to hold the clutch 85,186 engaged. Any, convenient controlmechanism, for example a lever 94" fulcrumed-on the gear-box 57 at 95and acting on the end of the bolt 87, and a Bowden wire 96 controlled bya hand lever on'the handles 98 of the, mower may bepr'ovided fordisengaging and engaging the clutch 85, 186 at will by the oper ator.Preferably, a 'th rust ball-bearing 99 is provided between the lever 94and bolt 87, a hardened steel pin 100 being carried by the lever 94 forco-acting withthe adjacent end of the bearing 99. A

' The transmission 56 to the back roller axle 87 comprisesreduction gearin the form of a slower motion sprocket wheel 86 (Figure 5) that isgeared by a chain 102 with said roller-driving sprocket wheel 84 andfast on the axle of a pinion 104 meshing with a spur gear 105 on theaxle 87 of the roller 24. This ,chain drive 56 and the'change-speed gear76, 7 7, 78, 79, as well as the chain drive 55 aforesaid of the rotarycutter 20, are all enclosed in said casin 12 which may be charged withoil to provi e an oil bath for the transmission mechanism. I

The back roller24 (Figure 5) is divided into three parts, namely twoenddrums 1 10, 111 mounted as described hereinafter freely rotatable onthe axle 87 journalled in said ball-bearings 25, 26, and a middle drum112. A differential gear of any convenient construction is preferablyprovided in the middle drum 112. As illustrated, this dilfcrential geardesignated generally by'the numeral 113 (Figures 5, 6 and 7) comprisestwo vided each on. a sleeve 116, 117 respectively that are freelyrotable one on each end of the axle 87 and carry respectively theend'drums 110, 111. K'eyed on the axle 87 between the sun-wheels 116,117 is a planet-wheel carrier 118 shown separately in Figure 7. Thiscarrier has four radial arms- 119, 120, 121, 122 arranged inpairs atopposite sides of a central boss 123,. the arms of each pair being notopposite one another, but staggered'anannular sun-wheels 114, formed orpro-v gularly one in relation to the other. Each of I these arms 119,120, 121, 122 carries respectively aplanet-wheel 124, 125, 126,127 whichinter-mesh in pairs 124, 125 and 126, 127,

whereof the wheels 125, 126 ,mesh with the annular sun-Wheel 114, andthe wheels 124, 127 meshwith the annular sun-wheel 115. A flanged ring130 of H-section has driving connection with the planet-wheel carrierbe-= tween the sun-wheels and is secured to the middle drum 112, theinner flanges of the ring 130 encircling the outer peripheries of thetwo sun-wheels. The axle 87 of the driving roller 24 is bored axiallyfrom each end towards the middle as shown at 131 to proextending eachthrouglra side member of the frame into the bores, for supplyinglubricant to the end drums. As illustrated, these tubes arescrew-threaded at theirouter ends in the side member of the frame andcarry a nut outside the latter, a feed hole being provided ii thescrew-threaded portion of each tube.

vide oil ducts, and two lubricating feed do vices, shown as o ling tubes132 are provided ,As shownin Figures 8 and ,9, the axle134' of the frontroller 27 is carried eccentrically and detachably by fiatted' or.squared ends in two adjusting arms 135, journalled each blade 140 vcutter 20 when in the other direction after at one end in one of theshown at 136, and carrying each at the other end a pin 137 extendingthrough an arcuate slot 138 in the adjacent side member, a clampmg screwin the form of a thumb nut or hand 1 wheel 139 being carried by each pin137 outside the side members of'the frame. This arrangement ensures thatthe arms 135. will move angularly in unison, so that the axle of thefront roller will move parallel to itself and the front roller will beat'the same height above the ground throughout its length.

A carrier of any convenient construction for carrying a ledger blade 140may be mounted on the distance rod. 16 aforesaid. A pre-'ferredconstruction of ledger-blade carrier is that disclosed in the saidprior patent. It'

is desirable to facilitate startin the engine of'a motor-drivenlawn-mower y relieving the cutter cylinder of the mower from allcontactwith the ledger blade and thereby obviating the resistance due tosuch contact during the starting operation. Accordingly, setting-meansfor the ledger blade are preferably provided comprising avmanuallyoperable gear in the form of a worm gear 141 so operativelyconnected with the carrier 142- of 'theledger blade as to shift thesamewhen'the gear 141 is rotated, in combination with a bushing 143rotatable manually in the side member all of the frame 10, in whichbushing the said gear 141 is so mounted as to be rotatable therewith andto be held against endwise movement in relation thereto, for the purposeof removing the ledger out of contact with the rotary starting theengine. In the preferred construction illustrated in Figure 10 the worm141 is so mounted as to permit of axial movement whilst in engagementwith a cooperating worm-wheel 146 arranged to rock the carrier 142 inknown manner, and

adjusting means are provided for shifting the Worm 141 endwise andthereby rocking said 143 con blade carrier 142. The bushing stitutes abearing for the worm spindle that is held against endwise movementtherein and is preferably held therein by friction against unintentionalrotation. The worm is thus journalled not directly in the frame 10, butin the bushing 143 which is screwed by a quick thread in the sidemelrnberll of the frame, and has a handle 144 inovable angularly throughabolut 180, its movement being limited by a stop 145 that abuts against144 is moved in such a direction that'the moved endwise and cooperateslike a toothed rack with its companion worm wheel 146 in the directionrequired to remove the ledger blade from contact with the rotary cutter.When the handle 144 is moved up to its limit the engine is side membersas i a plurality of pairs of and a controlling device for When the enfworm 141 is running the worm 141 returns the ledger blade to theposition in which it co-operates with the rotary cutter for the cuttingop eration. By' turning a knob 147 on the worm spindle the ledger bladecan be adjusted in the known manner in relation to the rotary cutter.This mechanism thus ,permits the ledger blade to be properly set inrelation to the rotary cutter for cutting purposes, which setting ismaintained when the blade is returned from its inoperative position toits cutting position after starting the engine.

An engine exhaust silencer 160 extends across the machine and has anelbow 164 at" its centre and a slip connection at 161 (Fig' ures 2 and3) with .the exhaust pipe of the engine which isarranged in thedirection of withdrawal of the power-unit and parallel to the crankshaft. A petrol tank 162 mount ed on theha'nd'les 98 is connected tothecarburetor 165 soas to be readily disconnected therefrom. For startingthe engine a handle may be applied .to the free endfof the shaft 51having a notch 163 for engagement by it.

It will be appreciated that the invention provides a power-driven lwn-inower suitable to be put in the hands o erator and able to withstandrious defects, such as high centre of gravity, considerable addition ofweight on the mower and increase in cost of manufacture and maintenance,due to the use of a water-cooled motor having a radiator arranged as isusual in motor-car practice are avoided by the improved construction, inwhich various modifications maybe made without departing from the scopeof the invention as defined ter and a driving roller journalled therein,frame, trans a power-unit carriedby said mission means bperativelyconnecting the power-unit withs aid cutter and said roller, whichtransmission means comprises an engine-driven. driving shaft and achange-speed gear driven by the latter, which changespeed gear is of thestep-by-step type having gear wheels of different gear ratios,

an unskilled opsevere use. Va-

the change-speed gear for selecting at will any of thesaid gear ratiosand thereby varying the speed of said cutter and roller in relation oneto the other and the speed of one of them in relation to that of thepower-unit,

or the purposes described. i I

2. A power-driven lawn-mower comprising the combination of a rigid sidemember constituting 'a casing frame having a whereof a part is in theform of a gear-box,

a rotary cutterand-a driving roller journalled in said frame, apower-unit carried by said frame, transmission means operativelyconnecting the power unit with said cutter and said roller, whichtransmission means comprises an engine-driven driving shaft that extendsinto said gear box, a change-speed gear that is housed in said gear boxand is driven by said drivingshaft, and

- driving means that is housed in said casing -a control device for thechange-speed gear for selecting at will any of said gear ratios;

3. A 'power-driven lawn-mower comprising in combination a frameincluding two rigid side members and cross members connecting the latterin spaced relation; part of one of which side members constitutes a gearbox, a rotary cutter and a driving roller journalled in said sidemembers, a power-unit mounted spaced away from said gear box on saidcross members, transmission means operativelyv connecting the power-unitwith said cutter and roller, which transmissionmeans comprises apower-unit-driven driving shaft that extends into said gear box, a

change-speed gear of the step-by-step type,

having a plurality of pairs of gear wheels of different gear ratios,which change-speed gear is housed insaid gear box and is driven by saiddriving shaft, and driving means that connects said change-speed gearwith said cutter and roller, and a self-adjustable coupling connectingsaid driving shaft with the shaft of the power-unit.

4:. A POWGf-dllVQItlilWIl-IHOWGI comprising the combination of a frame,arotary cutter and a driving roller journalled therein, a power-unitcarried by said frame, transmission means operatively connecting thepower-unit yvith said cutter and said roller,

which transmission means comprises an engine-driven driving shaft and achange-speed gear driven by the latter, which change-speed gear is ofthe step-by-step type having a plu-' rahty of pairs of gear wheels ofdifferent gear ratios, and a controlling device for the change-speedgear for selecting at will any of the said gear ratios and therebyvarying" the speed of said-cutter and roller in relation one to theother and the speed of one of them in relation tothat of the power-unit,which transmission means includes between the said change-speed gear andthe shaft of the rotary cutter a spring-controlled slip clutch adaptedautomatically to disconnect the powerunit from said cutter in the eventof the latter meeting with excessive resistance, and disengaging meansfor holding the clutch disengaged at will.

5. A power-driven lawn-mower comprising the combination of .a frame, arotary'cutter and a driving roller journalled therein,

a power-unit carried by said frame, transmission means operativelyconnecting the power-unit with said. cutter andsaid roller, whichtransmission means comprises an engine-driven driving shaft and achangespeed gear driven by the latter, which change speed gear is of thestep-by-step type having a plurality of pairs of gear wheels ofdiflerent gear ratios, and a controlling device for the change-speedgear for selecting atwill any of the said gear ratios and therebyvarying the speed of said cutter and roller in relation one to the otherand the speed of one of them in relation to that of thepower-unit,

which transmission means'includes between the said change-speed gear andthe shaft of the'rot'ary cutter a spring-controlled slip clutchcomprising clutch discs adapted auto matically to disconnect thepower-unit from,

said cutter in the event of the latter meeting with excessiveresistance, and disengaging means for holding the clutch' disengaged atwill, the operative faces of which clutch discs are adapted to give awarning sound when the clutch is slipping.

In testimony whereof I afiix my signature.

ARTHUR ERNEST JERRAMI

